Aluminum metal is generally manufactured by two techniques: the traditional Hall method, where an electric current is passed between two electrodes to electrolytically reduce alumina to aluminum metal; and the carbothermic method, where aluminum oxide is chemically reduced to aluminum via chemical reaction with carbon. The overall aluminum carbothermic reduction reaction:Al2O3+3C→2Al+3CO  (1)takes place, or can be made to take place, via a series of chemical reactions, such as:2Al2O3+9C→Al4C3+6CO (vapor)  (2)Al4C3+Al2O3→6Al+3CO (vapor)  (3)Al2O3+2C→Al2O (vapor)+2CO (vapor)  (4)Al2O3+4Al→3Al2O (vapor)  (5)Al→Al (vapor)  (6)
Reaction (2), generally known as the slag producing step, often takes place at temperatures between 1875° C. and 2000° C. Reaction (3), generally known as the aluminum producing step, often takes place at temperatures above about 2050° C. Aluminum vapor species may be formed during reactions (2) and (3), although aluminum vapor species may be formed via reactions (4), (5), and (6).